U.S. patent application number 10/754754 was filed with the patent office on 2004-08-05 for belt spool for a safety belt retractor.
This patent application is currently assigned to TRW Occupant Restraint Systems GmbH & Co. KG. Invention is credited to Blum, Herbert, Weller, Hermann-Karl.
Application Number | 20040149852 10/754754 |
Document ID | / |
Family ID | 7979608 |
Filed Date | 2004-08-05 |
United States Patent
Application |
20040149852 |
Kind Code |
A1 |
Blum, Herbert ; et
al. |
August 5, 2004 |
Belt spool for a safety belt retractor
Abstract
A belt spool (12) for a safety belt retractor with a frame has a
bearing (18) for a blocking catch (16) which can be moved from an
initial position in which the belt spool is freely rotatable, into
a blocking position in which it blocks the belt spool. The belt
spool further has a support surface (20) for the blocking catch
(16). The support surface (20) is provided with a projection (22;
26).
Inventors: |
Blum, Herbert; (Schwabisch
Gmund, DE) ; Weller, Hermann-Karl; (Alfdorf,
DE) |
Correspondence
Address: |
TAROLLI, SUNDHEIM, COVELL,
TUMMINO & SZABO L.L.P.
1111 LEADER BLDG.
526 SUPERIOR AVENUE
CLEVELAND
OH
44114-1400
US
|
Assignee: |
TRW Occupant Restraint Systems GmbH
& Co. KG
|
Family ID: |
7979608 |
Appl. No.: |
10/754754 |
Filed: |
January 9, 2004 |
Current U.S.
Class: |
242/383.2 ;
242/384 |
Current CPC
Class: |
B60R 22/36 20130101;
B60R 2022/286 20130101 |
Class at
Publication: |
242/383.2 ;
242/384 |
International
Class: |
B60R 022/405 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2003 |
DE |
203 01 518.5 |
Claims
1. A belt spool (12) for a safety belt retractor with a frame, said
belt spool comprising a bearing (18) for a blocking catch (16)
which can be moved from an initial position in which said belt
spool is freely rotatable, into a blocking position in which it
blocks said belt spool, and a support surface (20) for said
blocking catch (16), characterized in that said support surface
(20) is provided with a projection (22; 26).
2. The belt spool according to claim 1, characterized in that said
projection (22) is formed by a gentle curvature of said support
surface (20).
3. The belt spool according to claim 2, characterized in that said
curvature is constructed such that a rotation point of said
blocking catch (16) shifts when it is moved from said initial
position into said blocking position.
4. The belt spool according to claim 3, characterized in that said
rotation point of said blocking catch (16), in relation to a
direction of rotation of said belt spool in a belt band unwinding
direction, lies behind a line which runs through a contact point
between said blocking catch and a blocking toothing on said safety
belt retractor and a support point of said belt spool on said frame
of said safety belt retractor.
5. The belt spool according to claim 1, characterized in that said
projection is formed by a rib (26) which can be plastically
deformed.
6. The belt spool according to claim 5, characterized in that said
rib (26) is designed such that it is already deformable by said
blocking catch (16) at comparatively small forces.
7. The belt spool according to claim 5, characterized in that a
non-deformed region of said rib (26) forms an abutment surface (30)
for said blocking catch (16) which is effective in axial direction.
Description
TECHNICAL FIELD
[0001] The invention relates to a belt spool for a safety belt
retractor.
BACKGROUND OF THE INVENTION
[0002] A conventional belt spool typically has a bearing for a
blocking catch which can be moved from an initial position in which
the belt spool is freely rotatable, into a blocking position in
which it blocks the belt spool, and a support surface for the
blocking catch.
[0003] The belt spool with the blocking catch arranged on it is
rotatably mounted in a frame of the safety belt retractor. Provided
on the frame is a blocking toothing, into which the blocking catch
engages, when the latter is situated in its blocking position. For
moving the blocking catch from the initial position into the
blocking position, any desired release mechanism, known from prior
art, can be used, which responds in a belt band-sensitive or
vehicle-sensitive manner.
[0004] The invention is based on the problem of improving the
mounting of the blocking catch on the belt spool.
BRIEF SUMMARY OF THE INVENTION
[0005] According to the invention, a belt spool for a safety belt
retractor with a frame has a bearing for a blocking catch which can
be moved from an initial position in which the belt spool is freely
rotatable, into a blocking position in which it blocks the belt
spool. The belt spool further has a support surface for the
blocking catch. The support surface is provided with a projection.
This projection can serve two functions: Firstly, the projection
can be constructed as a gentle curvature of the support surface,
which is shaped such that the rotation point of the blocking catch
shifts when it is moved from the initial position into the blocking
position. This prevents a bent lever effect from occurring in the
case of high loads, in which the belt spool slightly works itself
into the frame, which effect makes difficult a return movement of
the belt spool; therefore the return movement of the blocking catch
from the blocking position into the initial position is only
possible to a very poor extent. Secondly, the projection can be
formed by a rib which can be plastically deformed and is designed
such that it is already deformable by the blocking catch at
comparatively low forces. This leads to the non-deformed section of
the projection, lying immediately adjacent to the blocking catch,
forming a contact surface acting in radial direction, which
supports the blocking catch against displacements in radial
direction. In this way, with minimum effort it can be prevented
that the blocking catch slips laterally from the support surface. A
contact surface effective in radial direction could basically also
be constructed from the outset in the manufacture of the belt
spool. As such a contact surface, however, represents an undercut,
a complicated slider would have to be provided in the die casting
tool used for the production of the belt spool. In addition, in the
region of the contact surface, burrs would inevitably occur, which
would have to be subsequently removed at a high expenditure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows a belt spool with a blocking catch according to
a first embodiment, the blocking catch being in the initial
position;
[0007] FIG. 2 shows the belt spool of FIG. 1, the blocking catch
being in the blocking position;
[0008] FIG. 3 shows a cutout of a belt spool according to a second
embodiment;
[0009] FIG. 4 shows the belt spool of FIG. 3 in a perspective view,
a blocking catch being shown which is in the initial position;
[0010] FIG. 5 shows the belt spool of FIG. 4, the blocking catch
being in the blocking position; and
[0011] FIG. 6 shows diagrammatically a section along plane VI-VI of
FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] In FIG. 1, a belt retractor 5 is shown diagrammatically,
which has as essential components a frame 10 and a belt spool 12.
The frame is provided with an opening, on the edge of which a
blocking toothing 11 is constructed.
[0013] On the end face of the belt spool 12, to be seen in FIGS. 1
and 2, a pocket 14 is formed, in which a blocking catch 16 is
arranged. The blocking catch can pivot from an initial position
shown in FIG. 1, in which it is arranged in the pocket 14 and does
not engage into the blocking toothing 11, into a blocking position
shown in FIG. 2, in which it engages into the blocking toothing 11.
This blocks the belt spool 12 against a rotation in an
anticlockwise direction, which corresponds to a blocking against a
belt band withdrawal. To swivel the blocking catch, any desired
control mechanism can be used which is known from the prior
art.
[0014] The blocking catch 16 has a bearing pin 18 which engages
into a recess in the belt spool 12 and forms the bearing for the
blocking catch 16, as long as the latter is in the initial
position. In addition, on the edge of the pocket 14 a support
surface 20 is constructed, which is provided with a gently curved
projection 22. The blocking catch 16 is provided with a
correspondingly curved counter-surface 24.
[0015] When the blocking catch is in its blocking position (see
FIG. 2), the counter-surface 24 lies against the support surface
20. Owing to the projection 22, the bearing pin 18 has no further
function, and a rotation point displacement occurs, because the
blocking catch is now able to pivot about the projection 22, if
only within certain limits. In FIG. 2, a line II is drawn, which
passes through the rotation point of the blocking catch when the
latter is in the blocking position, and through the contact point B
between blocking catch and blocking toothing 11. A line I is placed
through the rotation point of the blocking catch, which would be
determined by the bearing pin 18, as is the case in the prior art
with the blocking catch situated in the blocking position.
[0016] In FIG. 2 in addition, arrow P designates the region of the
blocking toothing 11 in which the greatest abutment forces of the
belt spool on the frame occur with high loads of the belt spool. As
the belt spool works itself slightly into the frame in the case of
high loads, it must rotate about this point P when it is turned
back in the belt band winding direction after high loads, in order
to return the blocking catch from the blocking position into the
initial position again.
[0017] If the belt spool is now turned in the belt band winding
direction, i.e. clockwise with respect to FIG. 2, the belt spool
rotates about point P, so that the bearing point of the blocking
catch moves downwards. With a construction according to prior art,
in which the blocking catch rotates about the bearing pin 18, the
two distances between point B and the bearing pin 18 on the one
hand and the bearing pin 18 and point P on the other hand form a
toggle-lever press; when the belt spool rotates about the point P,
the bearing pin 18 must "push apart" in an imaginary manner the two
points B and P. This leads either to high forces being necessary in
order to turn the bearing pin 18 so far downwards, until it lies
with the points P and B on a line and reaches the dead center of
the toggle-lever press, or else to the belt spool jamming with the
blocking catch, so that the blocking catch can no longer be
returned into the initial position.
[0018] In the structure according to the invention, on the other
hand, the rotation point of the blocking catch lies beneath the
straight connecting line between the points B and P, so that the
blocking catch, with a rotation in the belt band winding direction,
is pulled out directly from the blocking toothing. A jamming is
impossible.
[0019] In FIGS. 3 to 6, a second embodiment is shown. The
difference to the first embodiment consists in that on the support
surface 20, more precisely approximately centrally on the
projection 22, a rib 26 is arranged, which is aligned parallel to
the rotation axis of the belt spool 12. The rib 26 can be
plastically deformed, being designed such that it is already
deformed by the blocking catch 16 at comparatively low forces.
These forces lie considerably below those which act on the safety
belt retractor in an accident. For example, the rib 26 can be
designed such that it is plastically deformed by the blocking catch
16, more precisely it is pressed flat, at that forces which are
exerted by the vehicle occupant onto the safety belt and hence onto
the blocking catch with a hard braking of the vehicle.
[0020] In FIGS. 3 and 4, the rib 26 is shown in the initial state,
i.e. non-deformed. In FIGS. 5 and 6, the rib 26 is shown in the
state when plastically deformed. As can be seen in particular in
FIG. 6, a part of the rib 26 is pressed flat by the blocking catch
16, so that it no longer projects (or at least no longer
noticeably) over the support surface 20. Thereby, immediately
adjacent to the blocking catch 16 an abutment surface 30 is formed,
namely by the region of the non-deformed rib 26 lying adjacent to
the blocking catch 16. The abutment surface 30 prevents the
blocking catch 16 from slipping in axial direction outwards on the
support surface 20.
[0021] The particular advantage of the support surface 30 consists
in that it does not already have to be produced during the casting
of the belt spool, which in fact would lead to an undercut having
to be produced by a slider. Instead of this, the belt spool can be
cast without an undercut, and the abutment surface 30 is produced
automatically with the first higher stressing of the belt
retractor.
* * * * *